The subject matter disclosed herein relates to heat exchanger tubes. More specifically, the subject disclosure relates to a lubricant drying system for expansion of heat exchanger hairpin tubes.
Heat exchangers of, for example, air conditioners, include a plurality of heat exchanger fins and a plurality of heat exchanger tubes. The tubes are passed through holes in the fins, then are expanded to force the tubes into interference fit with the fins, thereby securing the tubes in place relative to the fins. The tubes include hairpin bend portions which are formed from straight tubes by bending, and then are expanded. Typically, the hairpin tubes are coated in lubricant prior to expansion, to prevent buildup of tube material (typically aluminum) on the expansion tooling, and also to reduce a force needed to expand the tube using the expansion tooling. The lubricant utilized, such as a dry-lubricant, is applied to the tubes wet, with the aid of a solvent. For optimal lubricant performance, and to achieve proper expansion, the solvent must be dried out of the tube prior to expansion of the tube to reduce variability, and resulting defects, during the expansion process.